Fracture resistance of polymeric wastes modified asphalt using R-curve and digital image correlation

Characterising the fracture properties of asphalt mixtures is a critical step toward a better pavement design. This study aims to investigate the mechanical response of asphalt mixtures modified with crumb rubber and plastic waste. These modified mixtures have been introduced in road construction based on the basic understanding of their mechanical properties. The R-curve based cumulative fracture energy and digital image correlation (DIC) technique were used to assess the fracture behaviour of the modified asphalt. The asphalt mixtures were examined under a monotonic semi-circular bending test for unconditioned, aged- and moisture-conditioned samples. The digital image analysis technique was used to construct the resistance curve based on the cumulative fracture energy. The DIC technique was used to capture the sample's strain field for the control and modified mixtures. Results showed that the rubberised asphalt promoted crack propagation, whilst plastic waste resisted cracking by prolonging the crack initiation phase compared to the conventional asphalt. Strain fields derived by DIC demonstrated different mechanical contributions for both modifiers under the fracture test.